Method of determining thermophysical properties of solid bodies

ABSTRACT

The invention is related to the methods of solid bodies&#39; thermophysical properties determination, particularly, to the methods of heat conduction and volumetric heat capacity determination. In accordance with the method heating of the reference sample and surface and sequentially located samples of the solid bodies in question is performed using a thermal energy source moving at a constant speed relative to the reference sample and samples-in-question. Excessive temperatures of the reference sample and samples-in-question at the points on the heating line are measured and by the excessive temperatures values the thermophysical properties are determined. Arbitrary shape samples are used and the samples&#39; heat conduction and volumetric heat capacity are determined by solving the inverse-factor heat conduction problem.

This invention is related to methods of determining thermophysicalproperties from solid bodies' (like rocks').

The correct record of the rocks' thermophysical properties, such asthermal conduction, thermal capacity and thermal diffusivity, becomes atop priority during industrial application of thermal productionenhancement methods providing prior simulation of the reservoir (oilformation) and borehole heat-mass exchange processes as well as theborehole equipment thermal mode determination.

The proposed method of solid bodies' thermophysical propertiesnon-destructive determination is different from the known methods (e,g.,Patent RU 2153664 or Patent RU 2011977) by the possibility to use onlyone experiment reference standard and enhanced measurementfunctionalities due to ensuring the measurement accuracy resulting fromthe reduction of the bias arising in the existing methods because of thesamples' surface curvature approximate record.

The purpose of the invention is to expand functionalities due toensuring volumetric heat capacity measurements and the measurements'accuracy improvement.

The proposed method of solid bodies' thermophysical propertiesnon-destructive determination, including the bodies with non-uniformproperties, includes the sample surface heating during the heating unitmotion relative to the sample with subsequent determination of excessivetemperatures based on which the thermophysical properties like thermalconduction and/or thermal diffusivity are determined. The method may beused for the samples of any shape and ensures wide-range heat conductionmeasurements (from 0.06 to 250 W/(mK).

The method of solid bodies' thermophysical properties determinationconsists in the heating the surface of the reference sample—a uniformfixed-dimension sample with the known constant heat conduction andvolumetric heat capacity, and the surfaces of the sequentially locatedsolid bodies' samples using a thermal energy source (Popov Yu. A. SomePeculiarities of Rocks' Heat conduction, Universities' Proceedings.Geology and Exploration., No. 4-1984, pp. 72-76.), moving with aconstant speed relative to the sample and the solid bodies' samples inquestion, measurement of excessive temperatures (i.e. the differencebetween the surface temperature and initial temperature) of thereference sample surfaces at the points on the heating line (the line onthe sample surface along which the heating source centre is moving) anddetermination of the samples' heat conduction based on the measurementsof the excessive temperatures of the reference sample and samples inquestion.

During the standard core measurements (a 30×30 mm cylindrical stick ofthe rock) and the use of a flat reference sample the excessivetemperature measurement results for the reference sample and the samplesin question are processed in such a way as using theoretical simulation(the process study using theoretical models—in this case—using anumerical solution) of physical processes accompanying the measurementprocess the difference of excessive temperatures for the flat andcylindrical surfaces is determined, then a set correction is applied tothe measured excessive temperatures.

During standard-core measurements an inverse-factor heat conductionproblem is solved (calculation of heat conduction factor or inversethermal capacity by the temperature values in certain points, James V.Beck, Ben Blackwell, Charles R. St. Clair, Jr/Inverse Heat ConductionIll-Posed Problems: Wiley Interscience Publication N.Y. 1989.-312 p.)and using the inverse heat conduction problem solution the heatconduction and volumetric heat capacity of the standard core cylindricalsamples is determined.

During flat-sample measurements the inverse-factor heat conductionproblem is solved and using the inverse-factor heat conduction problemsolution heat conduction and volumetric heat capacity of the flatsamples is solved.

During the method implementation the samples are located on the desk.The laser user as the thermal energy source is switched on ion theheating mode and moved along the line at a constant speed (2-4 mm/sec).The temperature measurements are held in series on the reference sampleand sample-in-question surfaces. Based on the solution to theinverse-factor heat conduction problem for the reference sample thethermal energy distribution law is restored. Based on the inverse-factorheat conduction problem solution the heat conduction factor value orvolumetric heat capacity value is restored.

1. A method of non-destructive determination of solid bodies'thermophysical properties determination including the reference samplesurface heating and the heating of the solid bodies samples' surfaceslocated in sequence with the reference sample; the heating is performedusing a thermal energy source moving at a constant speed relative to thereference sample and samples-in-question; measurement of the referencesample and samples-in-question excessive temperatures in the points onthe heating line and determination of thermophysical properties by theexcessive temperatures values characterized by the use of arbitraryshape samples and the determination of heat conduction and volumetricheat capacity by solving the inverse-factor heat conduction problem. 2.A method of non-destructive determination of solid bodies'thermophysical properties determination according to claim 1,characterized by the fact that during standard core measurements andflat reference sample use the excessive temperatures measurement datafor the reference sample and for the samples in question are processedin such a way that using theoretical simulation of physical processesaccompanying the measurement process the excessive temperaturesdifference is determined and a pre-set correction is introduced into themeasured excessive temperatures.